Issue:
The Activity LED on the Modbus Plus device is blinking in an unusual pattern. What do the Modbus Plus LED blink codes mean?
Product Line:
M340 Modbus Plus Proxy
TSXCUSBMBP
Quantum PLC
Environment:
Unity Pro
Ecostruxure Control Expert
Resolution:
Below you will find a similar Modbus Plus blink code table in the manual for each Modbus Plus device in question:
| One flash per second | The bridge plus node is offline after just being powered up, or after hearing a message from another node with the same network address (duplicate addresses are not allowed). In this state, the node monitors the network and builds a table of active nodes and token-holding nodes. It remains in this state for five seconds, then attempts to go to its normal operating state |
| Two flashes, then off for 2 s | The bridge plus node is hearing the token being passed among other nodes, but is never receiving the token. Check the network link for an open or short circuit, or defective termination. May also indicate a cable less than the minimum 10 feet in length between nodes. |
| Three flashes, then off for 1.7 s | The bridge plus node is not hearing any other nodes. It is periodically claiming the token, but finding no other node to which to pass it. Check the network link for an open or short circuit, or defective termination. |
| Four flashes, then off for 1.4 s | The bridge plus node has heard a valid message from another node that is using the same address as this node. The node remains offline in this state as long as it continues to hear the duplicate address. If the duplicate address is not heard for five seconds, the node then changes to the pattern of one flash every second. |
| Six flashes per second | This is the bridge plus is normal operating state. The node is successfully receiving and passing the token. All nodes on the network should be flashing this pattern. If a port indicator is off continuously, the bridge plus is not transmitting at that port |
| On Steady | The address switch setting is set to an invalid Modbus Plus address (i.e.: 0 or >64) |
Note: The blinking pattern of Six flashes per second can also be interpret ted as continuously blinking without pausing.
Released for:Schneider Electric Global
